Wheel spacers 101

[miketyler]

I have read several threads on wheel spacers and most (including myself) consider them more a liability than anything else. However, running the 315/35-17 on a 17x11 wheel on the rear with the stock Mustang BS I am going to have to have them. I got the rear wheels and estimate between .25-.50" inch to put the tire/wheel assembly in the middle of the well. Can I safely use the floating style spacer on this? The wheel is an AR TT2 with a 7" backspacing and isnt hubcentric.

I have also read that some prefer the bolt on "adapter" style spacers for thickness above .5".  I would like to run the stock Mustang wheel on the front as well but its a 9.5x17 wheel with a 6.375BS". Using the Percy tool I will easily need .75" or so just to clear zerk fitting on UBJ and tie rod end. Would aftermarket rotors change anything or do they maintain the stock hub Y location? I could go custom but the wait is 6-8 weeks. What do you experts think?   

[Hopalong]

I would think the bolt on spacer/adapter would be the way to go.  1/2" - 3/4" is a lot of spacers, which would require longer studs, which all say "Not for use with spacers".  I know that's probably a liabilty issue for the stud manufacturer, but so is the sticker that says you should not use your snow blower on the roof of your house. 

[miketyler]

yup - am less concerned with the back as its close and shouldnt need much. The fronts however will be considerable and with all the movement up there they need to be rock solid. How about upgrade front rotors and brakes? Do the aftermarket rotors displace the hub surface any or are they right on spec with original? I was considering upgrading and if it will help me run less spacer up front, it would be more convincing

[HP2]

Depending on wheel hub thickness, you may not be able to go over .25 spacer with the stock length wheel studs. Yes, the fixed, bolt down versions are the best, but I will admit to having heaped piles of abuse on .25 spacers with varying results. Of course, the quality of the spacers is also a point of concern with the cast aluminum universal design being bottom of the barrel and machined billet hub centric ones being best.

Most kits to adapt larger disc will also move the wheel spacing out as well. I know for sure the AR Engineering kit for 13" rotors is designed specifically to mount Mustang wheels in the correct spot. Wilwood also makes mention to check backspacing as it changes using their hub kits.

[miketyler]

My car will not see any race or high speed action and will have less than 5000 adult street miles a year driven on it. The 1/4 max floater rule then is more a limitation of stud length? Am prepared to replace studs with longer ones if need be. So my best laid plan is a machined aluminum, bolt-on, hub centric unit?

Will also check on improved offset for the front rotors. If these help me to keep my front spacer <1.0" and arent going to cost a fortune I would be interested in doing this upgrade now. 

[PlumCrazyChris]

Mike it looks like you already have the rims and tires, but according to Summit, the stock BS for a 94-00 mustang is 5.72"  The Ford Racing rims they sell TQ Thrust style are 17x8s with that BS for $129 ea.  Thats still 1.22 more BS than stock mopar 4.5, but a lot closer to what you need.

Maybe yours are from a different year range.

Good luck,

Chris

[miketyler]

Yes, I 've bought the tires and rear wheels but not the fronts. The 7" BS is supposed to be for the same effectivity but its an 11" wheel. I considered the smaller wheel and BS but really wanted to make the 275's work and the ideal rims size for them is 17x9.5.

I am not willing to give up a lot of driveability for this however and if I have to run monster spacers (or adapters being as large as it seesm they will be) I would rethink it and scale back to a 265 or thinner wheel.  The front 275/40-17's are a popular size for the rear of a lot of cars and I would just resell them.

With the 315's as wide as they are, and the body dropped 3", the 275's would give it a mean, track-ready look.   

[PlumCrazyChris]

I definately love the look.  What brand of tire did you say your running again? 

I'm really interested in seeing what size you will be able to fit on the front.  Do you have tubular upper control arms or something, because I never thought you could get more than a 245/60/15 on the front. 

With the bigger rims, I don't know exactly what you can get on there, so I can't wait to see what you come up with.

[miketyler]

what was minimum threads in bearing on lug bolts? I know its based on diameter, is it 1X the diameter of the bolt or more? Am about to try a 1/4" spacer and want to be sure i have anough stud showing thru. 

[GoodysGotaCuda]

I've heard ten lug nut revolutions

[miketyler]

wel I guess that's gonna take more than I have now. Studs are stock with .90" and with a .250 spacer you might have 3-4 turns. Maybe I should start looking at the rear disc conversion now. Might get a little front space that way. 

[GoodysGotaCuda]

I went with 3" studs to get proper thread engagement on my car
-Mike

[miketyler]

wow - those are lengthy! How much spacer were you running? I was thinking 1.5" long as I only would be losing 1/4"-5/16" depending on which spacer I used.

[GoodysGotaCuda]

I'm only running 7/16" worth of spacer, the wheels have pretty thick mounting flanges. I get about 99% of thread engagement on my closed end lugs. lol. They're close but clear just fine. If you have no spacer, then you may just need to zip some of that off and go.

-Mike